The following steps should help troubleshoot why you are unable to play DVDs on your computer:
Check to see if your DVD drive is functioning properly.
Make sure that your DVD drive is not empty.
If the DVD contains encryption, ensure that your computer has the proper software to decrypt the disc.
Make sure that the codecs required to play the DVD are installed on your computer.
If all of the above have been checked and double-checked, it is possible that your DVD disc is defective. Try playing the same disc on a different computer. You may also want to try cleaning the disc to see if that helps.
